Park - Engine Running (Mechanical Powerflow): Notes

WARNING: This page is about a different car, the 2020 Buick Regal and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

In Park range, there are three levels of power flow coexisting. The graphics will follow each flow separately by numerical designation, in relation to the following text.

1. Power From The Engine

Torque from the engine is transferred to the transmission through the engine flywheel which is bolted to the torque converter assembly (14).

2. Turbine Shaft Driven

As the torque converter turbine rotates, the 5-7-reverse and 6-7-8-9 clutch housing (530) and the turbine shaft (547) which is splined to the torque converter turbine, is also forced to rotate at turbine speed.

3. Input Sun Gear Driving

The input sun gear (551), which is splined to the turbine shaft (547), drives the input carrier assembly (552) pinion gears.

4. Input Carrier Assembly Driven

The input carrier assembly drives the output carrier assembly (555) pinions.

5. Output Carrier Assembly Held

The output carrier assembly (555) is splined to, and held by, the output carrier transfer drive gear hub (502). The output internal gear (input carrier assembly) (552) drives the output carrier assembly (555) pinions, which then drives the output sun gear (522).

6. Power Flow Terminated At The Output Sun Gear

Without the 1-2-3-4-5-6 clutch applied, torque cannot be transferred from the output sun gear (522), thus power flow is terminated.

7. Torque from Wheels to Front Differential Carrier Pinions

Torque from the vehicle travels through the wheels to the front differential carrier (238), and is transferred to the front differential carrier sun gear (240), which is splined to driven sprocket (241).

8. Park Gear Held/Power Flow Terminated at Front Differential Drive Pinion Gear Assembly

The park lock gear is held by the park pawl (715). The park lock gear is splined to the output carrier transfer drive gear hub (502). Therefore power flow is terminated at the output carrier transfer drive gear hub (502).

9. Drive Sprocket Held

The drive sprocket (234) is in mesh with the drive link (233), which is in mesh with and held by the driven sprocket (241).